From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8FDDD189513; Mon, 4 Aug 2025 00:29:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754267344; cv=none; b=um/agSdurQDeIgxGFimthpypytUIif4f11VGIneI3KOAPV0HrLkYkU9TbDp2Bx13jNluIm0DukqLWAs2PX+B/LMjmpC8YWB46zHaxaZ5dwUg1IwE6AyJmTtN/SyKRFC45T1gpWJ4EE+zeARkkVTh9LxWL6lGG8Q5i89UUi78DbA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754267344; c=relaxed/simple; bh=FMHCTzZK6FCit7hSKsiumX4ukzFlqY18rsL9r0zAe2k=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=k956RASylOEQsvjKY9fAlpmOlR0ADOQk8D2S8MqASlkrD0M2CBHrI3TgUnF2Ic8WtP+IFZGssrW6y3Vr+CcJBUxVH2McE9s1WLkrD8kzhwtDkRTL5mn+SafDEeHNXhSOcLMXsrQUlIfGi/vGp+4410oH8v5J4VTnbFq1wiRIKsc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iExlm3q2; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="iExlm3q2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2FC0BC4CEF0; Mon, 4 Aug 2025 00:29:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754267344; bh=FMHCTzZK6FCit7hSKsiumX4ukzFlqY18rsL9r0zAe2k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iExlm3q2axYpdI1McsGVimB8j09QqvG2rkyqzc6IXHgQAcdjJqZH0TZYSOFDwFbaz c1cWef86WgbZRJwLytew4x3J1ezOr/4pzYpXeC0K29l0TE8ME9uSGLMqj487HT9TVS AzEUMIFNGNxOIxO+NolKXrVXRQFfIOzVHaKYSL4akvnWfUwCLI9eGtyC9N1LdxAMi/ JAVGmdrLPxZ3qNvsrwlTZW4vqCHg0ft7KZxx9GwoA3knXouJ7a8kl1gWeiCEd0+4aZ ZTuASdEQzpc1OKyZWu7sJ2H+h92rdunJpZVydeJV/9R6kFgDHhlDDuNwGIMhDNmpUk XjWDRw6UD3N1g== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Kuninori Morimoto , Mark Brown , Sasha Levin , lgirdwood@gmail.com, linux-sound@vger.kernel.org Subject: [PATCH AUTOSEL 6.15 28/80] ASoC: soc-dapm: set bias_level if snd_soc_dapm_set_bias_level() was successed Date: Sun, 3 Aug 2025 20:26:55 -0400 Message-Id: <20250804002747.3617039-28-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250804002747.3617039-1-sashal@kernel.org> References: <20250804002747.3617039-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.15.9 Content-Transfer-Encoding: 8bit From: Kuninori Morimoto [ Upstream commit f40ecc2743652c0b0f19935f81baf57c601eb7f0 ] ASoC has 2 functions to set bias level. (A) snd_soc_dapm_force_bias_level() (B) snd_soc_dapm_set_bias_level() snd_soc_dapm_force_bias_level() (A) will set dapm->bias_level (a) if successed. (A) int snd_soc_dapm_force_bias_level(...) { ... if (ret == 0) (a) dapm->bias_level = level; ... } snd_soc_dapm_set_bias_level() (B) is also a function that sets bias_level. It will call snd_soc_dapm_force_bias_level() (A) inside, but doesn't set dapm->bias_level by itself. One note is that (A) might not be called. (B) static int snd_soc_dapm_set_bias_level(...) { ... ret = snd_soc_card_set_bias_level(...); ... if (dapm != &card->dapm) (A) ret = snd_soc_dapm_force_bias_level(...); ... ret = snd_soc_card_set_bias_level_post(...); ... } dapm->bias_level will be set if (A) was called, but might not be set if (B) was called, even though it calles set_bias_level() function. We should set dapm->bias_level if we calls snd_soc_dapm_set_bias_level() (B), too. Signed-off-by: Kuninori Morimoto Link: https://patch.msgid.link/87qzyn4g4h.wl-kuninori.morimoto.gx@renesas.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- LLM Generated explanations, may be completely bogus: Based on my analysis, here's my assessment: **Backport Status: YES** This commit should be backported to stable kernel trees for the following reasons: 1. **Bug Fix**: This is a clear bug fix that addresses an inconsistency in bias level management. The commit message clearly explains that `snd_soc_dapm_set_bias_level()` doesn't always update `dapm->bias_level`, particularly when dealing with card-level DAPM contexts where `snd_soc_dapm_force_bias_level()` is not called. 2. **Small and Contained**: The fix is minimal - it only adds 4 lines of code: ```c /* success */ if (ret == 0) snd_soc_dapm_init_bias_level(dapm, level); ``` This ensures that `dapm->bias_level` is always updated when the bias level change succeeds. 3. **Important Correctness Issue**: The inconsistency could lead to incorrect bias level tracking, which affects power management decisions in the ASoC subsystem. Code that checks `dapm->bias_level` (as shown in lines like `if (dapm->bias_level == SND_SOC_BIAS_ON)`) may make wrong decisions if the bias level isn't properly tracked. 4. **No Architectural Changes**: This is a straightforward fix that doesn't introduce new features or change the architecture. It simply ensures consistent behavior between the two bias level setting functions. 5. **Low Risk**: The change only affects the success path (when `ret == 0`) and uses an existing inline function `snd_soc_dapm_init_bias_level()` that simply sets `dapm->bias_level = level`. This is the same operation that `snd_soc_dapm_force_bias_level()` performs on success. 6. **Affects User-Facing Functionality**: Incorrect bias level tracking can lead to power management issues, potentially causing audio devices to not power up/down correctly, which directly impacts users. The commit fixes a real bug where the DAPM bias level state could become out of sync with the actual hardware state, particularly for card-level DAPM contexts. This is exactly the type of bug fix that stable kernels should include - it's small, targeted, fixes a real issue, and has minimal risk of introducing regressions. sound/soc/soc-dapm.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c index b7818388984e..227f86752b1e 100644 --- a/sound/soc/soc-dapm.c +++ b/sound/soc/soc-dapm.c @@ -739,6 +739,10 @@ static int snd_soc_dapm_set_bias_level(struct snd_soc_dapm_context *dapm, out: trace_snd_soc_bias_level_done(dapm, level); + /* success */ + if (ret == 0) + snd_soc_dapm_init_bias_level(dapm, level); + return ret; } -- 2.39.5